One way, at the command line....
Command: texteval
Enter new value for TEXTEVAL <0>: 1
Command: -text
Current text style: "L80" Text height: 3.20
Specify start point of text or [Justify/Style]:
Enter text: (strcat (getvar "dwgprefix")(getvar "dwgname")) "C:\\Projects\\2003\\23107\\dwg\\base.dwg"
Command: texteval
Enter new value for TEXTEVAL <1>: 0
Jeff